Corrosion coupons are small representative pieces of metal which are used to evaluate such things as system corrosivity, material performance, and corrosion inhibitor effectiveness. In order to be useful, a corrosion coupon must be placed in a representative location within the system to be monitored. This location must be representative in temperature, pressure, water chemistry, chemical additions, bacterial populations, and solids loading. The coupon must not cause turbulence in the flow stream, otherwise the coupon may corrode faster because of the erosional effects than the system to be monitored. Also, the coupon must be electrically isolated from the holder and from the system to be monitored, otherwise the coupon may corrode faster because of galvanic effects than the system to be monitored.